Background: Deep brain stimulation (DBS) is increasingly being used for treatment-resistant depression. Blinded, randomized controlled trials of active versus sham treatment have been limited to small numbers.

Objective: To conduct a systematic review and meta-analysis on the effectiveness of DBS in depression.

Method: The Cochrane Central Register of Controlled Trials, PubMed/Medline, Embase and PsycINFO, Chinese Biomedical Literature Service System and China Knowledge Resource Integrated Database were searched for single- or double placebo-controlled, cross-over and parallel-group trials in which DBS was compared with sham treatment using validated scales.

Findings: Eight papers from seven studies met inclusion criteria, all but one of which were double-blinded RCTs. We were unable to obtain data for a further unpublished study that was discontinued following a futility analysis. The main outcome was a reduction in depressive symptoms. It was possible to combine data for 96 participants. Patients on active, as opposed to sham, treatment had a significantly higher response (odds ratio (OR) = 6.73; 95% confidence interval (CI) = 2.91, 15.59; p < 0.0001) and reductions in mean depression score (standardized mean difference (SMD) = −0.54; 95% CI = −1.02, −0.07; p = 0.03). There were no differences for most other outcomes. Publication bias was possible.

Conclusions: DBS may show promise for treatment-resistant depression but remains an experimental treatment till further data are available.